The load control herein described has two main objectives. First, to maintain the energy output of the converters equal to demand and, second, to produce the energy conversion at least at cost. The first objective is obtained by establishing an error signal proportional to the difference between actual and required energy output and from this error signal generating a System Control Signal which operates to adjust all converters in parallel to maintain the total rate of energy output from the system equal to demand.
In accordance with accepted theory the rate of energy conversion required to satisfy a given demand is produced most efficiently when all converters in the system are converting energy at the same incremental cost. We achieve this, our second objective, by generating a System Incremental Cost Signal indicative of the incremental cost at which all converters in the system should operate and readjusting, under steady-state conditions, the rate of energy conversion of each unit until it is operating at this assigned incremental cost.
A primary objective of our invention is therefore to provide a load control wherein, generally, each of the energy converters immediately share in system load changes in proportion to its capability, but wherein the system load among the units is then readjusted, under steady-state conditions, so that each converter operates at the same incremental cost.
A further objective of this invention is to provide a load control of maximum flexibility wherein the components may be easily arranged or rearranged in accordance with the characteristics of the particular system to which it is applied.
These and other objectives will be apparent from the description to follow and from the drawing in which: